Poly(vinyl alcohol)/sacran hydrogel microneedles for anticancer transdermal drug delivery

Hydrogel microneedles (HMNs) are promising transdermal delivery systems. We prepared HMNs using a mixture of poly(vinyl alcohol) (PVA), sacran, and quaternised sacran (Q-sacran) crosslinked with citric acid (CA). The impact of the polymer composition, crosslinking time, and annealing temperature on the HMN properties was studied. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA) revealed the formation of networks composed of polymers containing CA and the corresponding HMNs. The highest swelling degree of HMNs was 440 ± 23%. Mechanical testing confirmed that HMNs were strong enough to penetrate the skin. The PVA/sacran HMNs were durable with a maximum force of 43 ± 1.2 N. These HMNs penetrated the Parafilm®-simulated skin up to 630-760 μm, while PVA/Q-sacran HMNs exhibited a penetration depth of 500 μm. The biocompatibility of HMNs was confirmed through cytotoxicity assays using L929 fibroblasts and B16F1 melanoma cells. The doxorubicin-loaded HMNs exhibited a controlled release profile and a potent anticancer activity against B16F1 melanoma cells. This work suggests that the PVA/sacran and PVA/Q-sacran HMNs can be used as new tools for transdermal drug delivery as mechanically tunable and biocompatible systems.